Dramatic changes in senior cats eye color?

My fur baby just passed over the rainbow bridge Monday, but preceding his death in the last month or so, I noticed his eyes changed drastically. He used to have bright lime green eyes, and before his death they were dark brown/orange and the pupil was irregular and more dialated than normal. Has anyone experienced this? The vet didn't see any signs of infection, and reported he seemed otherwise physically healthy, but told us we could see an opthamologist to further test. My fur baby passed quickly after that so we never made it to an eye doctor. I included the best photos I could find - when his health sharply declined I wasn't able to get a clearer photo of his eyes. The top photo is last year, and the bottom is this week.

I don't know about the color but the pupils doing that could have been a sign of something neurological, especially since it was both eyes.  She  could've had a stroke.

Thank you for your insight! It has been driving me crazy not knowing what happened to my sweet fur baby. After he passed, he was very jaundiced (he wasn't noticeably jaundiced before he passed), but the vet thought his cause of death was due to some kind of liver failure. The eyes don't seem to be a symptom of that from what I read though which is what is throwing me off!